Radio apparatus



F. LOWENSTEIN RADID APPARATUS Nov. 2 1926.

Filed May 23; 1921 8 Sheets-Sheet 1 F FRITZ LOWENfiTE/IY BY 44 14 TTOR/VE Y Nov. 2 1926'. 1,605,121

I F. LOWENSTEIN RADIO APPARATUS Filed May 23. 1921 8 Sheets-Sheet 2 INVENTOR. FR/T Z AOWfMSTE/A/ BY W p 'M ATTORNEY.

Nov. 2, 192a. 1,605,121

F. LOWENSTEIN RADIO APPARATUS Fil ed May 23. 1921 a sheets-shed: 5

g INVENTOR.

' FRITZ lawn/575w BY W W440 I l M ATTORNEY.

Nov. 2 1926.

F. LOWENSTEIN RADIO APPARATUS Filed May 23, 1921 8 Sheets-Sheet 4 INVENTOR. FR/ 7 Z Z OWEA/Sff/N BY W Wawww i A TTORNEY.

Nov. 2 1926.

F. LOWENSTEIN RADIO APPARATUS 8 Sheets-Sheet Lirll Filed May 25, 1921 INVEN TOR. fR/TZ zomfxvtsrfi/v BY 0%. W44

i m ATTORNEY.

Nov 2 1926 0 1 F. LOWENSTEIN J21 RADIO APPARATUS Filed May 23, 1921 8 Sheets-Shet 6 7 a: A TTORNEY.

Nov. 2 1926. 1,605,121 F. LOWENSTEIN RADI O APPARATUS Filed May 23, 1921 8 sheets sheet 8 &

l ilHllll INVEN TOR.

E/P/TZ mmews 7"//V BY W. (a m ATTORNEY.

WIJIM Y Patented Nov. 2, 1926.

UNITED STATES retain PTENr oFFIcE.

FRITZ LOWENSTEIN, OF NEW YORK, N. FRITZ LOWENSTEIN, DECEASED,

nnmmrsrnnron or sAI'n PATENTS CORPORATION, A DOMESTIC CORPORATION.

RADIO APPARATUS.

Application filed May 23, 1921. Serial No.471,634.

This invention relates to an improvement in radio transmitting apparatus.

The object of the invention is to provide an apparatus of this kind which will be very compact, of simple construction, and highly efficient.

The invention consists in the features of construction, proportions of the coils and combinations of elements as will be more fully described in connection with the accompanying pointed out.

I11 the accompanying drawings,

Fig. 1 represents diagrammatically an arrangement of circuits embodying the principles of the invention;

Fig. 2 is a front View of transmitter apparatus embodying the invention;

Fig. 3 is a plan view of the apparatus shown in Fig. 2;

Fig. 4: is an end view looking from the right in Fig. 3, the end panel of the casing being removed and parts being shown in section on the line H of Fig. 3;

Fig. 5 is a rear view in elevation of the front panel of the apparatus;

Figs. 6 and 7 are detailed sections on the line 6-6 and 7-7 of Fig. 3;

Figs. 8 and 9 are front and respectively, vice and with;

Fig. 10 is a fragmentary sectional View on an enlarged scale illustrating a detail of said variometer device;

Fig. 11 is a detail in horizontal section of a part of the mechanism for actuating the antenna variometer;

Fig. 12 is a diagram with table referred to hereinafter, and

Fig. 13 is a diagrammatic view of a modification of the invention.

Referring first more particularly to Fig. 1, M, G, designate a motor generator set delivering alternating current of suitable frequency to the primary P of a transformer having a secondary S. A condenser is connected across the secondary S. One side of the condenser and transformer secondary is connected through spark gap 21 to a heliedge views, of the antenna varlometer departs immediately associated theredrawings and then particularly cal inductance coil 22 forming what I will call the primary coil; while the opposite side of the condenser. and transformer secondary is adjustably connected through movable switch arm 23 to said primary 22, said switch arm being arranged to move over contact devices 24, which are connected, respectively, by leads 25 to adjusting tap points 26 on said primary Winding.

The antenna A is connected through lead 27 and a variometer device 28, 29, to a variable point 30 on a helical inductance coil 31 which in the present case is inductively related to coil 22 and co-operates therewith. Variable tapping points 32 on said coil 31 are connected by leads 33 to contact devices 3 1 over which is arranged to sweep movable switch arm 35, said arm being connected by conductor 36, 37, 38, and variometer device 39, 4:0 to a variable contactv point 4C1 on the primary coil 22. Connection of the antenna circuit to ground is completed through variable contact 42, lead 43, hot wire ammeter 44 and lead l5.

The two movable switch arms 23, 35, are

arranged to be simultaneously moved by common actuating means over their respective sets of contact devices 2st, 34, to vary the operating wave length as may be desired. As here shown, the said switch arms are coupled together for simultaneous movement by intermeshing segmental gears 16, 47. In order to avoid the undesirable effect of dead end turns in the secondary coil 31, the end of said coil acent the primary coil is permanently connected by lead 33 to end contact 34 of the secondary series of contact devices, which in turn is connected through leads 37, 38, etc. to the primary 22.

As shown, the secondary inductance coil 31 is co-axial with the primary coil 22 and somewhat spaced therefrom though partly within inductive range thereof. It is evident therefore that the primary and secondary circuits of the system are inductively coupled and at the same time conductively coupled. As will appear more fully hereinafter, the relative dimensions of the primary and secondary coils, the spacing apart thereof, and the exact arrangement of the various IOU connections to said coils, are matters of great importance in attaining one of the important objects of the invention, namely, a transmitter construction of such character that operation can be had'atany one of a plurality of different wavelengths selectively without having to alter the mechanical coupling of the two circuits, that is to say, without shiftingthe position of the ground connection or of the coupler connection il on the primary inductance coil and without altering the distance between the coils 22 and 31. Before going into a discussion of how this object may be attained in practice and formulating a general controlling law. it will be desirable to describe a typical transmitter construction embodying the general circuit arrangements already described, and such a construction is here illustrated in Figs. 2 to 11 inclusive.

Referring to these drawings, the essential parts of the apparatus are supported on a casing or framework comprising front panel 50, end panels 51 and 52 extending rear- \mrdly at right angles therefrom, and intermediate panel 53 disposed between said end panels. Said panelsare of non-conducting material, and are secured together rigidly by sets of rods 54 and 55 which are either composed of or covered with non-conducting material. The primary and secondary inductance coils 22 and 31 are composed of flat copper ribbon wound spirally, the coil 22 being supported within the circular series of rods 54, and the coil 31 being similarly supported within the circular series of rods 55. The primary coil tapping points 26 and secondary coil tapping points 32 are shown as sli-dable clips engaging the proper turns of the primary and secondary coils, respectively. The said tapping points are connected by their respective leads 25 and 33 to the two sets of contact devices 2% and 3 which are in the form of contact studs mounted on the transmitter casing or framework. The contact studs 24 are mounted on the front face of the front panel, while the secondary contact studs 34 are mounted on a supplemental panel 56 located a short distance to the rear of the front panel and extending parallel thereto between the panels 52 and 53. The switch arms 23 and 35 sweep over the respective sets of contact studs 24 and 34, switch arm 23 being mounted in front of the panel on its rotatable controlling shaft 57; while switch arm 35 at the rear of the panel 50 is secured to a hub 58, rotatable in abearing provided in the said panel 50. Said hub 58 carried secured thereto the beforementioned gear segment 47 which meshes with a similar gear segment 46 fixedly secured to shaft 57. Accordingly, when shaft 57 is turned by means of its controlling knob 59, said switch arms 23, 35, are simultaneously swung over their respectively co-operating sets of contact studs, but in opposite directions, to make the proper connections to the primary and secondary inductance coils for operation at anyone of the difierent wave lengths for which the 1p 'lhe-antenna variometer before referred to, comprises generally the rotatable shaft 28 extending axially within the secondary inductance coil 31 and journaled at its opposite ends in the casing panels 52, 53, as shown, and the double cross arm 2 SHPPQI'L- ed on said shaft in a manner to be more fully hereinafter described. Said arm is of non-conducting material and in. this instance is of rectangular cross section, except at its j ournaled ends. @n opposite sides shaft 28 carries strips 62 of metal which are metah lically connected to the metal bearing pivot 33 in which said shaft 28 terminates at the end adjacent the antenna lead 27. The a n tcnna lead 27 is connected to a binding post 64., said binding post 64 being connected to said pivot 63 by means of a wiping brush connection 65. The double cross arm 29 is so mounted on shaft 28 as to be compelled to rotate therewith but to be slidable longitudinally thereon. Said cross arm is of nonconducting material in this instance, and it carries at its opposite ends bifurcated met-ailic shoes or contact devices (36 and 67, each of which contact shoes fits over the inner edge of the copper ribbon conductor forming the secondary inductance coil. One of said contact shoe devices, in this instance, is electrically connected by means of a metal strip 8 and brushes 69, with said metal strips (32; while the other contact shoe device 6? remains insulated from said strips and therefore serves in this case merely as a guide device. By rotating the shaft 28, the guide devices 66 and G7 follow the helical turns of the primary 'coil 31, the cross arm 29 being at the same time moved longitudinally along the shaft 28, the connection of the contact member 66 to the antenna through the sliding brush arrangement just described being continuously maintained. In this way, the portion of the secondary inductance coil actively in the antenna circuit may be adjusted as required.

The variometer device 39, 4:0 to which the secondary switch arm 35 is connected is similar in all essential respects to the varioineter device 28, 29, just described, and its constructiontherefore does not require detailed explanation. The shaft 39 of the primary variometer device is journaled at one end in panel 51 and at the other end has a metal pivot 39 journaled in an auxiliary panel 70 which also serves to carry the ends of rods 54. The'shaft 39 may be rotated to adjust the primary or coupling variometer by means of the knob 71. Any adjustable means may be provided for rotating the shaft 28 of the antenna variometer. In this instance said shaft carries a beveled gear 72 meshing with a beveled pinion 73, said pinion being fast on a shaft 74 which is supported by and extends through a fixed bushing or bearing sleeve 75 upon which the hollow shaft 57 of the primary switch arm control is revolubly carried. The shaft 74 has an operating knob 76 secured to the outer end thereof and projecting slightly beyond the controlling knob 59, as shown. 7

The leads, 36, 37, and 38, connecting the secondary switch'arm to the shaft 39 of the primary coupling variometer are clearly indicated in Figs. 3, 5 and 11. A spring waslr or 39 insures good contact between metal collar 39" pinned to pivot 39 and lead 38.

In case of extreme variations in the length of the antenna, either through accident or otherwise, it may be desirable to alter the normal angular relation of the switch arms 23, 35 with respect to each other, in order to effect adjustments necessitated by such eX- treme variations. One way of providing for this is illustrated in Fig. 6, where the primary arm 23 has a hub 77 loose on a bushing 78 that is secured in any suitable manner to hollow shaft 57 (made of insulating material), for rotation therewith. Said arm 23 carries a latch 79 pivoted thereon, said latch being adapted to enter any one of several notches 80 provided in the cover plate 81. Leaf spring 82 engaging said latch member 79 tends to hold it either in the operative coupling'position shown in Fig. 6, or to hold it in inoperative position when the latch is turned up out of coupling position by lifting on the knob 83.

The spark gap 21 is of the quenched type, comprising a plurality of elementary spark gap units 84 supported. inholder arms 85 on the lower part of panel 50, said gap units, when supported as shown being in end to end contact and therefore connected in series. As the construction of the spark gap forms no part of the present invention, detailed description thereof is deemed unnecessary. The respective ends of the complete quenched gap are connected in the closed oscillation circuit by leads 86, 87, as shown.

The apparatus hereinbefore described contains a number of advantageous mechanical features, but a particularly important feature is the relative dimensioning of the primary coil, the secondary coil, and their relation to each other. In Fig.'12 I have given a diagram indicating the two coils as well as their measurements, and in connection with this diagram I have given a table setting forth the measurements of the various dimensions indicated in the diagram, these measurements being stated 1n 1I1Cl'lQS,1I1tIl1I1S of winding for the respective coils, and in ratios, to the diameter of the primary coil. The dimensions are taken from a completed apparatus which gave highly successful results working on an antenna having a capacity of .0005 microfarads. On this diagram, Fig. 12, G indicates the tapping point for the ground lead; 25 means turns; figures in a circle indicate ratio to the diameter of the primary coil, and figures with the double prime mark indicate inches. The table comprises two parts, the left hand table referring to the primary coil, while the right hand table refers to the secondary coil. lVave lengths are indicated by the Greek letter A. Turns of the primary are indicated by 13 and turns of the secondary are indicated by t,. The other headings for the lines will be obvious from the explanation hereinbefore given.

The point where the lead from the loading inductance or secondary coil is connected to the primary coil is indicated at H. V

The end of the primary coil to which the primary circuit has the continuous connection, is indicated at Z.

The antenna connection with the secondary or loading coil is indicated at .W, it be ing understood that the said secondary or loading inductance should be provided with two extra turns outside this antenna connection.

Although in Fig. 12 I have given measurements in inches, in the subsequent discussion of methods and calculation I will employ the units of the metric system.

The distance measured on the primary coil in centimeters from the end Z (Fig. 12) to the point G will hereafter be known as g, the corresponding distance from the end Z to the coupling connection H will hereafter be designated as h.

The length of the primary coil from the end Z to the point where the lead of highest wave length connects, and which in some cases will be practically the total length of the primary coil, I will hereafter refer to as the length 12.

In the design of an apparatus embodying the present invention, if the ratio of the capacity of the primary circuit to the capacity of the antenna circuit is substantially 8, that is, if

a new apparatus may be designed by first selecting a suitable diameter for the primary coil and then designing the other dimensions of the primary and secondary in accordance with the ratios given in the diagram, Fig. 12, and in the accompanying table. In practice, the ratio of these capacities is about of the value given for the one-half kilowatt and one kilowatt sets.

In order, however, to enable those skilled in the art to design apparatus embodying my invention for various conditions, I give the following explanations of the method of procedure:

One knows the capacity (C of the primary circuit, the capacity (C of the secondary circuit, the coupling, K, which it is desired to maintain, and the wave lengths at Which the apparatus is to work. lVith this information one proceeds as follows:

Find the value of Vith this value as the argument, enter the Table T (given below) and take out the corresponding values 9., and h If the exact argument does not appear in the first column, the table may be interpolated in any suitable manner, as for example, by graphic methods, that is to say, by plotting the value of g as ordinates with the corresponding values of the argument c; We.

as abscissae, on a relatively large scale, drawing a smooth curve through the points for the given ordinates, and then with the particular argument, measuring the desired 9 By the same graphic method the value of b for any argument may be determined with sufficient accuracy for practical purposes.

With g as the argument enter the Table T (given below), the value of (/0 being found in the first column designated Z From this take out the. corresponding value in the column, L which I will designate as L Also with it, as an argument enter the table T and take out the corresponding value in the column L.,, which value I will designate as L Let indicate the lowest wave length of the various wave lengths given.

One now finds the value of the self inductance of that part of the coil extending from that end where one primary lead is fixed to the point where the ground lead is to be connected. This value (L is given by the following formula:

L (meters) (18849 C (m. f.)

L (microh.)

From the values L L and P, one proceeds todetermme the diameter of the primary coil, by the following formula Yext, one determines the distances, 9 and h of the ground and coupling leads iron'i the end of the C011 nearest it, thus 1) lb h l) Now one can determine the wave length AH of the coil at the above mentioned distance it A H G L0G This gives the essential, dimensions of a primary coil with purely conductive coupling from wave length \.(j to the wave length a and if this range covers all the wave lengths required, the second coil may be a pure loading coil, that is, it may be placed out of inductive reach of the primary. The positions for the taps for the desired wave lengths between a and i need not be calculated, because they may be found by tuning, it being understood that all the tapping leads have variable connections to the coil.

Where the wave length range is to be extended to higher values than a detern'iined as hereinbefore explained, it is necessary to resort to some inductance coupling between the primary and secondary circuits, and this is done by extending the length of the primary coil to a value e which will be mostsatisfactory if not much greater than h+.5D, and may be less if desired. Assuming it to be h-l-mD:

With the value of 4; determined and m selected, one next proceeds to find the wave length A at the point '0. First one finds a value '0 as follows:

o zh +m Entering table T with n as an argument, one takes out the corresponding value in column L which value I will designate L Then one determines M as follows:

L.v /L...

liltl primary coil was extended substantially beyond the length it to the length 4) and the open circuit coil is to be placed with some turns in inductive relation to the primary coil, that is to say, is to have some turns acting as a secondary and the others as mere loading coils.

The total inductance L, of the antenna circuit is found as follows:

(188 9 0 The total inductance L includes the inductance L of that part of the primary coil included in the antenna circuit, as well as the inductance L of the antenna, and, of course,

must include the inductance L of the open circuit coil. That is To calculate. L, we proceed as follows:

o o go From table T with 0., as the argument, one takes the. corresponding value in column li wlnchvalue I will designate L The value of the inductance L being found, the coil is to be suitably propor tioned. In practice, it is well for present purposes to have the ratio of length to diameter about 1.5. Some departures from this ratio, which I will designate l are permissible, but it is advisable not to depart too far.

With Z as the argument one takes from the table T the corresponding value in the column L which I will designate as L The pitch of the secondary coil is determined by usual practice and will probably be about as stated in table Q hereinbefore referred to. This selected pitch I will designate as P The diameter D of the second or loading coil may now be determined, as follows:

If the open circuit coil is a mere loading inductance, it is left out of substantial inductive relation to the primary.

If, however, the open circuit coil is to be used asa secondary to the primary, it must be properly adjusted in coaxial relation thereto in order to give a proper coupling.

To do this, adjust the two circuits in resonance at the longest wave length )t with the ground G and the coupling H at the calculated points; then move the secondary relative to the primary coil until the best coupling is obtained. Then secure the secondary coil in this position. The coupling will be automatically maintained at substantially the value for which the apparatus was designed, throughout all the wave lengths.

The taps for the secondary are determined as explained for the primary coil.

While the coupling of the apparatus dewhen necessary of a condenser or an inductance in any one of the leads between the contact point of the quick-change switch and the variable connector for such lead. The condenser may be used in the primary circuit or in the secondary circuit. Individual condensers for correcting coupling are shown in the secondary circuit at w in Fig. 13. They are not subjected to high potentials and hence need not be expensive.

' Instead of using individual condensers w for correcting the coupling as above indi cated, it is sometimes advantageous to employ individual inductances in the said leads, as indicated at 3 Fig. 13. i

In the practical construction of an apparatus for a definite situation, the secondary and loading coil may be fixed in place after its proper relation to the primary coil has been determined by test as hereinbefore explained. However, in order to provide apparatus of more flexibility, the combined secondary and loading coil may be mounted adjustably with relation to the primary coil in such a way that it will remain in any adjusted position.

It will be noted that in my construction the primary coil has a series of coupling turns between the points G and H (Fig. 12) and that the primary circuit always includes a number of turns in the direction of Z (Fig. 12) which I will designate as beyond the coupling turns. In other words, the coupling turns are never at the extreme end of the coil where the non-variable connection of the primary is made. This is an important features of my invention, and this construction, coupled with the proper designing of the coil, enables me to obtain the advantageous results of a practically constant coupling, throughout all the wave lengths.

The apparatus specifically shown and described is intended for transmission in connection with spark gaps, that is to say, for

uenched spark gap operation. However, t e primary coil, the loading inductance or lift! secondary coil, and their associated switching mechanism'and adjusting devices may be employed in any transmitting system, whether employing arcs, tubes or generators, and, furthermore, may be used as the tuning apparatus in receiving sets, in which case, of course, the circuits and coils would be designated reversely from their present designations, that to say, what is referred to hereinbeforc as a primary cricuit would be call-ed a 559001162133," circuit in a receiving a pparatus, and vice versa. lrlore generically, the circuits may be referred to as the open circuit and the closed circuit.

The tables referred to in the specification are as follows:

Table Q.

KW' C1 C2 P1 P2 Table T Table T l zg 7%, 11 0 What I claim is:

1. In a radio apparatus, a closed circuit, an inductance coil inductively related to said circuit, a transformer coil connected nonvariably with said circuit at one end and having all its coupling turns away from that end of the coil at which the non-variable connection of the closed circuits is made and having the distances of the beginning and end respectively of the coupling turns from said end so proportioned with respect to the turns of said inductance coil that a substantially uniform coupling will be maintained, substantially as described.

2. In a radio apparatus, the combination with an inductance coil having an antenna connection near one end and a transformer connection near the other end, of a transformer coil having its magnetic field arranged to envelop the magnetic field of said inductance coil and arranged to have one end connected to one end of a closed circuit, means for making a ground connection and a coupling connection for the transformer connection of said inductance coil, whereby a portion of the turns of the transformer serve as conductive coupling turns, all of said coupling turns being away from that end of the transformer coil to which the closed circuit is connected as aforesaid, a series of contacts for the transformer coil, a series of indi vidual leads running from said contacts to tapping points on the transformer coil. a series of contacts for said inductance coil, a series of individual leads running from the latter contacts to tapping points on the said inductance, means for making a connection from the conductive connection of the transformer coil to any desired contact point of said inductance, and means for making a connection from the closed circuit to any one of the contact points of the t 'ansformer coil.

3. In a radio apparatus, the combination with an inductance coil having an antenna connection near one end and a transformer connection near its other end, of a transformer coil arranged to have one end connected to one end of a closed circuit, means for making a ground connection and a coupling connection for the transformer connection of said inductance coil, whereby a portion of the turns of the transformer serve as conductive coupling turns, all of said coupling turns being away from that end of the transformer coil to which the closed circuit is connected as aforesaid, a series of contacts for the transformer coil, a series of individual leads running from said contacts to map ping points on the transformer coil, a series of contacts for said inductance coil, a series of individual leads running from the latter contacts to tapping points on the said inductance, a pair of switching means for making a connection from the conductive connection of tl e transformer coil to any desired contact point of said inductance, means for making a connection from the closed circuit to any one of the contact points of the transformer coil, and mechanism interconnecting said switching means for operating both said switching means simultaneously whereby movement of one switching means imparts movement to the other switching means.

4. In a radio apparatus, the combination with an inductance coil having, an, antenna Iii) connection near one end and a transformer connection near its other end, of a transformer coil arranged to have one end connected to one end of a closed circuit, means for making a ground connection and a coup ling connection for the transformer connection of said inductance coil, whereby a portion of the turns of the trans former serve as conductive coupling turns, all of said coupling turns being away from that end of the transformer coil to which the closed circuit is connected as aforesaid, a series of contacts for the transformer coil, a series of individual leads running from said contacts to tapping points on the transformer coil, 21 series of contacts for said inductance coil, a series of individual leads running from the latter contacts to tapping points on the said inductance, a plurality of switching means for making a connection from the conductive connection of the transformer coil to any desired contact point of said inductance, means for making a connection from the closed circuit to any one of the contact points of the transformer coil, and mechanism for operating said switching means separately and simultaneously whereby movement of one of said switching means imparts movement to the other of said switching means.

5. In a radio apparatus, the combination with an inductance coil having an antenna connection near one end and a transformer connection near the other end, of a trans former coil arranged to have one end connected to one end of a closed circuit, means for making a ground connection and acoupling connection for the transformer connection of said inductance coil, whereby a portion of the turns of the transformer serve as conductive coupling turns, all of said coupling turns being away from that end of the transformer coil to which the closed circuit is connected as aforesaid, the distances of the beginning and end of the said coupling turns from said end being so proportioned that a suitable coupling will be maintained, a series of contacts for the transformer coil, a series of individual leads running from said contacts to tapping points on the transformer coil, a series of contacts for said inductance coil, a series of individual leads running from the latter contacts to tapping points on the said inductance, variable means for making a connection from the conductive connection of the transformer coil to any desired contact point of said inductance, and variable means for making a connection from the closed circuit to any one of the contact points of the transformer coil, said variable means being simultaneously adjustable whereby adjustment of one of said means effects corresponding adjustment of the other of said means.

6. In a radio apparatus, the combination with a coil proportioned to determine various suitable wave lengths, a separate coil arranged to act inductively on said first mentioned coil, a series of contact devices, leads from each contact device to a corresponding tapping point on the first mentioned coil, each lead having a variable connection to said first mentioned coil, an individual.

impedance device arvarying the number of turns of the two coils being in engagement to move in unison, and an antenna connection for the other coil.

8. In a radio apparatus, the combination of a pair of coils placed end to end and both inductively and conductively connected, a circuit containing means for energizing one of said coils, one end of said circuit being connected to the coil to be energized at a point remote from the other coil, means for varying the number of turns of the coil to be energized and connected to said circuit, a ground conductor connected to the coil to be energized at a point remote from the other coil, means for varying the number of turns of the other coil to be conductively connected to the coil to be energized, and an antenna connection for the other coil, the means for so varying the number of turns of the two coils being joined so as to operate in unison.

9. high frequency signaling apparatus comprlsing in combination a pair of inductance coils axially aligned and connected inductively and conductively, a circuit for energizing one of said coils, said circuit be ing connected to the coil to be energized at a point remote from the other coil, means for including a variable number of turns of said coil to be energized in said circuit, a connection to the other of said coils with a radiating system, means for varying the effective number of turns included in circuit with said radiating system, each of said means being simultaneously operative in such manner that motion of one of said means imparts corresponding motion to the other of said means.

10. A high frequency signaling apparatus comprising in combination an oscillatory circuit, a radiating circuit, a pair of inductances each fixed in spacial relation with re spect to each other and inductively and conductively associated, connections between one of said inductance-s and said oscillatory circuits, connections between the other of said inductances and said radiating circuit, and means simultaneously operative for adjusting the effective number of turns of said inductances included in .the respective circuits, the movement of one of said means serving to impart corresponding movement to another of said means for etl'ecting the tuning of said circuits and adjusting the coupling thereof without change in the spacial relation of said inductances.

11. A high frequency signalin apparatus comprising in combination an oscillatory circuit, a radiating circuit, a pair of inductances each fixed in spacial relation with re spect to each other and inductively and conductively associated, connections between one it said inductances and said oscillatory circuit, connections between the other of said in'cluctances and said radiating circuit, a pair of separate switching devices for varying the effective number of turns out said inductances included in said oscillatory circuit and said radiating circuitrespectively, said switching devices being geared together in such manner that movement oi one of said switching devices operates to impart simultaneous movement to the other of said switching devices for controlling the cou pliug between said inductances without varying the spacial relation thereof.

A signal transmittingapparatus comprising in combination a high frequency osclllatory circuit, a radiating circuit, a pair of independent inductance coils each axially aligned end to end arranged one in the magnetic held of the other, a connection between said inductance coils, connections between one of said inductance coils and said oscillatory circuit, connections between the other ot said inductance coils and said radiating circuit, and switching means for each of said inductance coils for controlling the eltective number of turns thereof in said circuits and a mechanical actuator extending between said switching means for etiect'ing simultaneous movement thereof whereby the movement of one oi said switching means operates to produce a corresponding move ment oi? the other of said switching means tor variably controlling the coupling between said circuits without change in the spacial relation of said inductance coils.

FRITZ LOW ENS EIN.

Pill 

